Uplink Control Signaling Density Adaptation for 5G Unlicensed Spectrum
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Solution Overview
Problem
Current 5G NR systems operating in unlicensed spectrum face challenges in reducing latency for uplink control signaling due to periodicity of LBT procedures, which can lead to increased overhead and resource reservation inefficiencies.
Innovation Solution
Implementing multiple configurations of uplink control signaling opportunities, with a higher density outside of the channel occupancy time (COT) to reduce latency and overhead, by configuring smaller periodicities or more resources per opportunity, and using LBT procedures tailored to COT conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LBT procedures are performed periodically in unlicensed spectrum, then channel access is ensured and coexistence is maintained, but latency for uplink control signaling increases
Solution Approach 1:
The patent segments uplink control signaling opportunities into two distinct configurations: one for inside COT (with higher periodicity) and one for outside COT (with lower periodicity). This segmentation allows the system to optimize latency for outside-COT transmissions while maintaining reliable channel access through periodic LBT procedures inside COT.
Solution Approach 2:
The patent implements dynamic selection between different uplink control signaling configurations based on COT conditions. The UE determines whether to use the first or second configuration based on whether the transmission occurs inside or outside COT, allowing adaptive optimization of latency and resource utilization according to real-time channel conditions.
2Loss of time
If higher density of uplink control signaling opportunities is configured outside COT, then latency is reduced, but overhead increases
Solution Approach 1:
The patent applies local quality by configuring different densities of uplink control signaling opportunities in different temporal regions: higher density outside COT where latency is critical, and lower density inside COT where channel access is already guaranteed. This localized optimization reduces overall overhead while maintaining low latency where needed.
3Reliability
If resource reservation is increased for uplink control signaling, then reliability is improved, but resource utilization efficiency decreases
Solution Approach 1:
The patent applies partial action by configuring uplink control signaling opportunities selectively based on COT conditions. Instead of reserving resources continuously, the system provides higher resource density only when needed (outside COT), and reduces resource reservation inside COT where channel access is already reliable, thereby improving overall resource utilization efficiency.
Data Source
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AI summary
Uplink signaling in unlicensed or shared spectrum may be subject to listen before talk procedures resulting in failed signaling transmissions. A user equipment (UE) may perform uplink signaling using a configuration based on whether a base station has entered a channel occupancy time (COT) shared with the UE. A UE may determine that the UE has an uplink transmission for a base station. A UE may determine whether the base station has entered a channel occupancy time that is shared with the UE. A UE may determine configured random access or scheduling request transmission resources based on the channel occupancy time, wherein a density of transmission opportunities is greater outside of the shared channel occupancy time than within the shared channel occupancy time. A UE may transmit a random access message or the scheduling request on selected configured resources.